Anti-Human Immunodeficiency Virus Type 1 Activity of the Nonnucleoside Reverse Transcriptase Inhibitor GW678248 in Combination with Other Antiretrovirals against Clinical Isolate Viruses and In Vitro Selection for Resistance

Abstract

GW678248, a novel nonnucleoside reverse transcriptase inhibitor, has been evaluated for anti-human immunodeficiency virus activity in a variety of in vitro assays against laboratory strains and clinical isolates. When GW678248 was tested in combination with approved drugs in the nucleoside and nucleotide reverse transcriptase inhibitor classes or the protease inhibitor class, the antiviral activities were either synergistic or additive. When GW678248 was tested in combination with approved drugs in the nonnucleoside reverse transcriptase inhibitor class, the antiviral activities were either additive or slightly antagonistic. Clinical isolates from antiretroviral drug-experienced patients were selected for evaluation of sensitivity to GW678248 in a recombinant virus assay. Efavirenz (EFV) and nevirapine (NVP) had >10-fold increases in their 50% inhibitory concentrations (IC 50 s) for 85% and 98% of the 55 selected isolates, respectively, whereas GW678248 had a >10-fold increase in the IC 50 for only 17% of these isolates. Thus, 81 to 83% of the EFV-and/or NVP-resistant viruses from this data set were susceptible to GW678248. Virus populations resistant to GW678248 were selected by in vitro dose-escalating serial passage. Resistant progeny viruses recovered after eight passages had amino acid substitutions V106I, E138K, and P236L in the reverse transcriptase-coding region in one passage series and amino acid substitutions K102E, V106A, and P236L in a second passage series.

EASY-HIT: HIV Full-Replication Technology for Broad Discovery of Multiple Classes of HIV Inhibitors

“…this technology was validated with a panel of nine known HIV inhibitors that target different processes of HIV replication, beginning from the very early processes of viral attachment and entry and extending through reverse transcription, integration, transcription, and production of infectious virions ( Table 1). The 50% effective concentrations (EC 50 ) of all tested drugs were consistent with published data for various T-cell lines and HIV isolates (22,27,29,37,40,51). Testing of the reference compounds in time-of-addition assays showed that this technology can also be used in secondary assays for higher-resolution discrimination of different steps of the replication cycle, facilitating the classification of inhibitor activities.…”

Inhibition of HIV‐1 or bacterial activation of macrophages by products of HIV‐1‐resistant human cells

“…Introduction of novel, more effective anti‐HIV‐1 treatments is still a priority and much of the research potential is directed to improve current, and to implement future antiviral therapeutics 1 , 2 , 3 , 4 , 5 . Some of these novel treatments target the function of HIV‐1 reverse transcriptase through a novel non‐nucleoside reverse transcriptase inhibitors 2 , 5 or inhibit the expression of viral RNA through siRNA silencing 3 . Others utilize multiple novel mechanisms of action to impede HIV by targeting host cellular proteins that are not susceptible to mutation 6 …”

Dual Enzyme-Linked Immunosorbent Assay System for Detection of Endogenous Kinase Activities of Mitogen- and Stress-Activated Protein Kinase-1/2

“…The phosphorylation of CREB/ATF1 is specifically caused via the p38-MSK1/MSK2 pathway with anisomycin stimulation, as observed in primary embryonic fibroblasts derived from knockout mice that do not express MSK1, 16 The 95% confidence interval (CI) value is that for the IC 50 value. Error bars represent standard error of n ϭ 3 values.…”